This invention relates to on-off sprinkler heads for fire extinguishing systems, and in particular to a sprinkler head with a reciprocating valve and offset drive motor arrangement.
Sprinkler heads are used in automatic fire extinguishing systems for buildings, and the like, to quickly extinguish and/or control fires therein. Conventional sprinkler heads include a fusible element which melts at a predetermined temperature, and opens the valve portion of the sprinkler head to permit a fire extinguishing fluid, such as water, to be sprayed therefrom into the area surrounding the sprinkler head. Such sprinkler heads are of the "one-shot" type, in that they do not automatically close and reset once the fire in the associated area has been extinguished. Rather, such sprinkler heads continue to emit water until the central water supply valve has been shut off.
On-off sprinkler heads have been developed with actuator and drive motor assemblies, which automatically open and close the valve portion of the sprinkler head in response to temperature variations within the associated environment, such that the same can cycle on and off as required. In this manner, the on-off sprinkler head provides maximum water pressure to the hottest areas of the fire, and simultaneously alleviates unnecessary water damage in those areas in which the fire has been extinguished.
Some on-off sprinkler heads, such as those illustrated in U.S. Pat. No. 3,874,455, are provided with reciprocating valves to control the flow of fire extinguishing fluid therethrough. This reciprocating valve arrangement typically obstructs and impedes the flow of fluid through the valve, and thereby decreases the fire fighting effectiveness of the device. Heretofore, such sprinkler heads also included various operative elements, such as supports, springs, and the like, which are disposed directly in the emitted stream of the fire extinguishing fluid, thereby seriously disrupting the spray pattern discharged from the head. Also, such designs require a specially shaped deflector plate, which can not be easily interchanged with other deflector plate designs to adapt a single sprinkler head configuration to a variety of spray patterns and/or different applications.